Misdiagnosis Malpractice Claims

What Is Misdiagnosis Malpractice?

Misdiagnosis malpractice — also called diagnostic negligence — arises when a healthcare provider's failure to reach a correct diagnosis meets the legal standard for malpractice: the diagnostic process fell below the accepted standard of care, and that failure caused measurable harm to the patient.

Not every wrong diagnosis is malpractice. Medicine involves uncertainty, and some conditions present with symptoms that could reasonably support multiple diagnoses. The legal question is whether the physician followed a diagnostic process that a reasonably competent physician in the same specialty would have followed given the information available at the time.

The three categories of diagnostic failure that most commonly give rise to malpractice claims are:

Failure to diagnose (missed diagnosis)

The physician fails entirely to identify a condition that was present and diagnosable — for example, failing to identify a pulmonary embolism in a patient presenting with pleuritic chest pain, tachycardia, and a recent history of immobility.

Wrong diagnosis

The physician identifies the wrong condition — for example, diagnosing muscle strain in a patient actually presenting with a myocardial infarction, or diagnosing a benign cyst when the lesion is malignant.

Delayed diagnosis

The correct diagnosis is eventually made, but after an unreasonable delay that allowed the condition to progress to a more advanced and less treatable stage.

The Diagnostic Process and Where It Fails

The diagnostic process — taking a history, performing an examination, generating a differential diagnosis, ordering appropriate tests, and integrating the results — has well-defined standards. Diagnostic malpractice typically arises from failures at identifiable points in this process:

• Failure to take an adequate history (e.g. missing family history of cancer)
• Failure to perform a sufficient physical examination
• Failure to consider the correct diagnosis in the differential
• Failure to order appropriate diagnostic testing (imaging, biopsy, lab work)
• Misinterpretation of imaging or laboratory results
• Failure to act on abnormal results — including failure to communicate critical results to the treating physician or to the patient
• Failure to refer to a specialist when the diagnosis exceeds the physician's competence
• Premature closure — settling on a diagnosis without adequately considering alternatives

Commonly Missed and Misdiagnosed Conditions

Research from the Agency for Healthcare Research and Quality (AHRQ) and the National Academies of Sciences identifies a consistent set of conditions most frequently involved in diagnostic error claims — conditions that are time-critical, treatable when caught early, and devastating when missed:

• Cancer (particularly breast, colorectal, lung, and skin)
• Myocardial infarction (heart attack)
• Stroke and transient ischemic attack
• Pulmonary embolism
• Sepsis
• Meningitis
• Aortic dissection and abdominal aortic aneurysm
• Spinal epidural abscess
• Ectopic pregnancy
• Appendicitis

Missed and Delayed Cancer Diagnosis

Missed and delayed cancer diagnoses are among the most frequently litigated categories of diagnostic malpractice. Common scenarios include:

• Failure to follow up on an abnormal mammogram, Pap smear, or PSA result
• Misinterpretation of a biopsy by a pathologist
• Failure to order recommended cancer screening at appropriate intervals
• Failure to refer for diagnostic biopsy following a suspicious imaging finding
• Misreading of a chest X-ray or CT scan that contained a visible lung nodule
• Dismissing patient symptoms as non-cancer-related without adequate workup

The harm in delayed cancer cases is the difference between the treatment and outcome the patient would have had with timely diagnosis and the treatment and outcome they actually received. This may include more aggressive surgery, additional chemotherapy, reduced survival probability, or — in the most serious cases — a previously curable cancer becoming terminal.

Missed Cardiac Events: Heart Attack and Aortic Dissection

Failure to diagnose acute coronary syndrome in the emergency room is a recurring source of malpractice claims. Patients — particularly women, younger patients, and patients with atypical symptoms — are discharged from emergency departments with diagnoses of gastroesophageal reflux, anxiety, or musculoskeletal pain when they are in fact experiencing acute myocardial infarction.

Aortic dissection is another high-stakes missed diagnosis. The classic presentation — sudden tearing chest or back pain — is often atypical, and dissection is missed in initial presentations in a substantial proportion of cases. Untreated thoracic aortic dissection carries a mortality rate of approximately 1% per hour during the first 48 hours.

Establishing breach in cardiac misdiagnosis cases often turns on whether the physician obtained an ECG, ordered cardiac biomarkers (troponin), considered the clinical decision rules for chest pain, and arranged appropriate observation or admission rather than discharge.

Causation: The Central Challenge in Misdiagnosis Cases

Causation is the most difficult element to prove in a misdiagnosis case. The plaintiff must establish that, more likely than not, the delayed or missed diagnosis caused the injury complained of. This requires expert evidence on what would have happened with timely correct diagnosis — the counterfactual outcome.

In cancer cases, this typically means expert testimony on stage progression, treatment options at the earlier stage, and survival probabilities by stage. In cardiac cases, it means expert testimony on what intervention would have been undertaken with earlier diagnosis and how that intervention would have changed the outcome.

The traditional preponderance standard — more likely than not — can create harsh results in cases where the underlying disease carried poor prognosis even with timely diagnosis. If a patient with stage 4 cancer at the time of presentation had a 60% mortality risk regardless of when diagnosis was made, the traditional rule would bar recovery for the loss of the 40% chance of survival.

The Loss of Chance Doctrine

A number of states have adopted a loss of chance doctrine to address the harshness of the traditional causation rule in delayed diagnosis cases. Under loss of chance:

• The plaintiff may recover where the defendant's negligence reduced the plaintiff's chance of a better outcome — even if that chance was less than 50%
• Damages are typically calculated proportionally — for example, if negligence reduced survival probability from 40% to 20%, the plaintiff may recover 20/40 (or 50%) of the damages that would have been awarded for a complete deprivation of survival

A minority of states have adopted some form of the loss of chance doctrine — including Washington (Herskovits v. Group Health Cooperative, 1983), Massachusetts (Matsuyama v. Birnbaum, 2008), Montana, and New Mexico. The contours of the doctrine vary significantly between recognizing jurisdictions, and a number of states have considered and rejected it. The majority rule remains traditional preponderance causation. Whether — and in what form — loss of chance is available is a state-specific question that must be confirmed with current local authority.

Whether loss of chance is available in your state is a critical threshold question in any delayed diagnosis case.

Damages in Misdiagnosis Cases

Damages in misdiagnosis cases reflect the difference between the outcome the patient would have had with timely correct diagnosis and the outcome the patient actually experienced. They typically include:

• Cost of additional, more aggressive treatment necessitated by the delay
• Pain and suffering associated with the avoidable progression of disease
• Lost wages and lost earning capacity
• Reduced life expectancy
• Wrongful death damages where the misdiagnosis was fatal

In states that recognize loss of chance, damages may be reduced proportionally to reflect the patient's baseline prognosis. Full guide to medical malpractice damages →

Statute of Limitations for Misdiagnosis

The discovery rule is particularly important in misdiagnosis cases. In most states the limitations clock does not start until the patient discovers (or reasonably should have discovered) both the injury and its connection to the diagnostic failure. In a delayed cancer diagnosis case, this is typically when the cancer is finally diagnosed at a later stage.

Full guide: Statutes of limitations by state →